The present invention relates to a method for the dehydrating distillation of an aqueous solution of a carboxylic acid such as acetic acid with high thermal efficiency.
Several methods are known in the prior art for the separation of water from an aqueous solution of a carboxylic acid such as acetic acid by distillation including a method in which dehydration is performed by the extraction of acetic acid with an organic solvent followed by azeotropic distillation of the solvent and water and a method in which dehydration is performed by the direct azeotropic distillation of an aqueous solution of the carboxylic acid with admixture of an organic solvent to remove the solvent and water with omission of the procedure of extraction.
Although less disadvantageous in respect of the thermal energy consumption than other methods using no organic solvent, the above mentioned methods still have a problem of the costs for a large quantity of thermal energy required to remove the organic solvent and water in the dehydrating azeotropic distillation.